YUVImage instance
* serves as the destination image for YUV encode and decompress-to-YUV
* operations and as the source image for compress-from-YUV and YUV decode
* operations.
*
* Technically, the JPEG format uses the YCbCr colorspace (which technically is
* not a "colorspace" but rather a "color transform"), but per the convention
* of the digital video community, the TurboJPEG API uses "YUV" to refer to an
* image format consisting of Y, Cb, and Cr image planes. In this image
* format, the Y, Cb (U), and Cr (V) planes are stored sequentially in the same
* image buffer, and the size of each plane is determined by the image width,
* height, line padding, and level of chrominance subsampling. If the
* chrominance components are subsampled along the horizontal dimension, then
* the width of the luminance plane would be padded to the nearest multiple of
* 2 (same goes for the height of the luminance plane, if the chrominance
* components are subsampled along the vertical dimension.) For instance, if
* the source image is 35 x 35 pixels and 4:2:2 subsampling is used, then the
* luminance plane would be 36 x 35 bytes, and each of the chrominance planes
* would be 18 x 35 bytes. If you specify, for instance, a line padding of 4
* bytes on top of this, then the luminance plane would be 36 x 35 bytes, and
* each of the chrominance planes would be 20 x 35 bytes.
*/
public class YUVImage {
private static final String NO_ASSOC_ERROR =
"No YUV buffer is associated with this instance";
/**
* Create a YUVImage instance with a new image buffer.
*
* @param width width (in pixels) of the YUV image
*
* @param pad Each line of each plane in the YUV image buffer will be padded
* to this number of bytes (must be a power of 2.)
*
* @param height height (in pixels) of the YUV image
*
* @param subsamp the level of chrominance subsampling to be used in the YUV
* image (one of {@link TJ#SAMP_444 TJ.SAMP_*})
*/
public YUVImage(int width, int pad, int height, int subsamp)
throws Exception {
setBuffer(new byte[TJ.bufSizeYUV(width, pad, height, subsamp)], width, pad,
height, subsamp);
}
/**
* Create a YUVImage instance from an existing YUV planar image
* buffer.
*
* @param yuvImage image buffer that contains or will contain YUV planar
* image data. See {@link YUVImage above} for a description of the image
* format. You can use {@link TJ#bufSizeYUV} to determine the appropriate
* size for this buffer.
*
* @param width width (in pixels) of the YUV image
*
* @param pad the line padding used in the YUV image buffer. For
* instance, if each line in each plane of the buffer is padded to the
* nearest multiple of 4 bytes, then pad should be set to 4.
*
* @param height height (in pixels) of the YUV image
*
* @param subsamp the level of chrominance subsampling used in the YUV
* image (one of {@link TJ#SAMP_444 TJ.SAMP_*})
*/
public YUVImage(byte[] yuvImage, int width, int pad, int height,
int subsamp) throws Exception {
setBuffer(yuvImage, width, pad, height, subsamp);
}
private void setBuffer(byte[] yuvImage, int width, int pad, int height,
int subsamp) throws Exception {
if (yuvImage == null || width < 1 || pad < 1 || ((pad & (pad - 1)) != 0) ||
height < 1 || subsamp < 0 || subsamp >= TJ.NUMSAMP)
throw new Exception("Invalid argument in YUVImage()");
if (yuvImage.length != TJ.bufSizeYUV(width, pad, height, subsamp))
throw new Exception("YUV image buffer is the wrong size");
yuvBuf = yuvImage;
yuvWidth = width;
yuvPad = pad;
yuvHeight = height;
yuvSubsamp = subsamp;
}
/**
* Returns the width of the YUV image.
*
* @return the width of the YUV image
*/
public int getWidth() throws Exception {
if (yuvWidth < 1)
throw new Exception(NO_ASSOC_ERROR);
return yuvWidth;
}
/**
* Returns the height of the YUV image.
*
* @return the height of the YUV image
*/
public int getHeight() throws Exception {
if (yuvHeight < 1)
throw new Exception(NO_ASSOC_ERROR);
return yuvHeight;
}
/**
* Returns the line padding used in the YUV image buffer.
*
* @return the line padding used in the YUV image buffer
*/
public int getPad() throws Exception {
if (yuvPad < 1 || ((yuvPad & (yuvPad - 1)) != 0))
throw new Exception(NO_ASSOC_ERROR);
return yuvPad;
}
/**
* Returns the level of chrominance subsampling used in the YUV image. See
* {@link TJ#SAMP_444 TJ.SAMP_*}.
*
* @return the level of chrominance subsampling used in the YUV image
*/
public int getSubsamp() throws Exception {
if (yuvSubsamp < 0 || yuvSubsamp >= TJ.NUMSAMP)
throw new Exception(NO_ASSOC_ERROR);
return yuvSubsamp;
}
/**
* Returns the YUV image buffer
*
* @return the YUV image buffer
*/
public byte[] getBuf() throws Exception {
if (yuvBuf == null)
throw new Exception(NO_ASSOC_ERROR);
return yuvBuf;
}
/**
* Returns the size (in bytes) of the YUV image buffer
*
* @return the size (in bytes) of the YUV image buffer
*/
public int getSize() throws Exception {
if (yuvBuf == null)
throw new Exception(NO_ASSOC_ERROR);
return yuvBuf.length;
}
protected long handle = 0;
protected byte[] yuvBuf = null;
protected int yuvPad = 0;
protected int yuvWidth = 0;
protected int yuvHeight = 0;
protected int yuvSubsamp = -1;
};